Typically, the luminance of a liquid crystal display device is controlled by changing the intensity of light outputted from a backlight. The intensity of the output light from the backlight is generally controlled by changing the duty ratio for turning on or off the current passing through the backlight. Such a control method is commonly called PWM dimming. PWM dimming has an advantage that it can be realized using a simple circuit configuration. On the other hand, PWM dimming has a disadvantage that so-called flicker, where the screen flickers, occurs due to the turn-on/off of the backlight, particularly, when the duty ratio is low.
To compensate for this disadvantage, Patent Literature 1 performs so-called phase-shift control, that is, divides a backlight into five backlight blocks and sequentially turns on the backlight blocks while shifting the turn-on start timing. Thus, flicker can be reduced compared to when all the backlight blocks are turned on or off simultaneously.